Method of manufacturing molds, dies or forming tools having a porous heat exchanging body support member having a defined porosity

ABSTRACT

Described are molds, dies and forming tools comprising: a) a heat exchanging body support member; and b) within the support member, a molding cavity portion formed by thermal spraying metallic particles to a desired configuration in the support member. Also described are methods of making a mold, die or forming tool comprising the steps of: a) providing a body support member having a controlled and designed porosity which permits the enhancement of the heat transfer ability of said mold, die or forming tool; b) configuring a surface of the support member to a desired cavity; and c) spraying particles to the configured cavity in the support member, thereby producing a mold, die or forming tool. Preferably, the materials of construction are metallic and are applied by thermal plasma spraying. The particles may also be ceramics, metal matrix composites, ceramic matrix composites, thermoplastic resins, thermoset resins, and composites based thereupon. The controlled porosity of the body of the mold, die and/or forming tool is as important as the use of thermal spray to subsequently form the cavity.

CROSS REFERENCE TO RELATED APPLICATION

[0001] This application is a continuation of U.S. Ser. No.: 08/349,252,filed Dec. 5, 1994, now U.S. Pat. No. 5,609,922, issued Mar. 11, 1997.

TECHNICAL FIELD

[0002] The present invention relates to the fields of molds, dies, andother forming tools, their manufacture and their use in metalmanufacturing and plastic manufacturing.

BACKGROUND ART

[0003] Molds are generally metallic and are comprised of a body portionand a cavity portion. A key feature to increased productivity formolding operations is to dissipate the heat that is generated during themolding process. In other words, the faster one can dissipate the heatin the molding operation, the faster one can increase the cycle time formolding.

[0004] Molding is used as a technique for fabricating metallic articlessuch as in shaping process. Molding is also used for the formation ofthermoplastic and thermoset, as well as elastomeric materials which aregenerally characterized as plastic materials.

[0005] Thermal spraying is generally characterized as a group ofprocesses in which finely divided metallic or non-metallic surfacingmaterials are deposited in a molten or semi-molten condition on aprepared substrate to form a spray deposit. “Thermal spraying” is a termgenerally applied to such other processes called arc spraying, flamespraying, and plasma spraying. The thermal spraying gun generates thenecessary heat by using combustible gases or an electric arc. As thematerials are heated, they change to a plastic or molten state and areaccelerated by a compressed gas. The confined stream of particles areconveyed to the substrate. The particles strike the surface, flatten andform thin platelets (splats) that conform and adhere to theirregularities of the prepared surface and to each other. As the sprayedparticles impinge upon the substrate, they cool and build-up, particleby particle, into a lamellar structure, thus a coating is formed. See“Thermal Spraying”, Practice, Theory and Application, published by theAmerican Welding Society, Inc. of Miami, Fla. (1995).

[0006] Plasma spraying is a thermal spraying process in which anon-transferred arc is utilized as the source of heat that ionizes a gaswhich melts and propels the coating material to the workpiece.

[0007] Flame spraying is a thermal spraying process in which an oxyfuelgas flame is the source of heat for melting the surfacing material.Compressed gas may or may not be used for atomizing and propelling thesurfacing material to the substrate.

[0008] Arc spraying is a thermal spraying process utilizing an arcbetween two consumable electrodes of surfacing materials as a heatsource and a compressed gas to atomize and propel the surfacing materialto the substrate.

[0009] U.S. Pat. No. 3,429,962 discloses a thermal spray technique offorming a metallic oxide article. A rotatable mandrel 15 of, forexample, copper or aluminum, has applied thereto a metallic oxide. Thefinal product is obtained by chemically etching away the copper oraluminum mandrel. The end product is utilized as a fuel cell electrode.In a similar fashion, U.S. Pat. No. 5,006,321 pertains to the thermalspray method of producing glass mold plungers.

[0010] U.S. Pat. No. 4,460,529 describes the process of manufacturing aceramic hollow body by the thermal spray technique. The ceramic bodiesare composed of aluminum and titanium carbides, borides, nitrides andmixtures thereof. The appropriate core material is selected so that itwill not bind with the ceramic material. The reference indicates thatthe detachability of a mold core from the hollow body can be assured bythe choice of a core with a higher coefficient of expansion relative tothat of a ceramic or ceramic oxide layer.

[0011] U.S. Pat. No. 2,968,083 describes a hot patching of refractorystructures utilizing a spraying of metal.

[0012] Other patents of interest include U.S. Pat. Nos. 5,290,373;4,966,220; 5,000,244; 4,482,513; 4,304,747; 4,242,074; 4,547,415;4,460,529; 3,916,418; 4,006,633; and 3,609,829.

[0013] It has been stated that spray deposits utilizing thermal sprayingdo not add strength to the substrate. Thermal spraying, supra at page16. The present application, however, does utilize a body that can becooled very quickly and the use of thermal spraying onto the body informing the cavity of the mold allows for the design of a mold whichwill have extremely high strength to permit molding of plastic as wellas metallic articles.

[0014] It is an object of the present invention to describe a mold ordie having a body portion and a cavity portion wherein the cavityportion is formed in the body portion by means of a thermal sprayingtechnique.

[0015] It is another object of the present invention to describe themanufacture of molds or dies having a body portion and a cavity portionwherein the cavity portion is formed by a thermal spraying technique.

[0016] It is a further object of the present invention to describe themanufacture of plastic or metallic parts by molding the desiredmaterials in a mold that has a body portion and a cavity portion whereinthe cavity portion is formed by thermal spraying metallic particles intothe body portion.

[0017] It is a further object of the invention to describe a bodyportion of the invention which permits very high cooling rates and highflexibility in formation of a cooling means for the body.

SUMMARY OF THE INVENTION

[0018] Described is a mold or die comprising a porous heat exchangingbody support member having a defined porosity; and within the supportmember a molding cavity portion formed by applying a metallic surface toa desired configuration in the support member.

[0019] Also described is a method of making a mold or die comprising thesteps of:

[0020] (a) providing a porous heat exchanging body support member havinga defined porosity;

[0021] (b) configuring a surface of the support member to a desiredcavity; and

[0022] (c) applying to the configured cavity in the support member ametallic surface thereby producing a mold or die.

BRIEF DESCRIPTION OF THE DRAWINGS

[0023]FIG. 1 is a schematic view of the mold or die of the presentinvention;

[0024]FIG. 2 is a cross-section of the mold or die of the presentinvention taken along lines 2-2 of FIG. 1;

[0025]FIG. 3 is a schematic process describing the manufacture of themold or die of the present invention;

[0026]FIGS. 4 and 5 show a schematic process for molding and releasing aplastic product.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0027] In the present application, the invention is broadly related tomolds, dies, and other forming tools. The technology applies to toolsthat are used for the manufacture of parts based on thermoplasticresins, thermoset resins plus class, metals and alloys.

[0028] For metals, molds means tools used for casting only. Dies areused for either forming or casting. One is able to produce dies andmolds for the casting (such as die casting) and for the forming ofmetals (such as pressing a sheet or billet into a shape).

[0029] For glass part fabrication, molds and dies are used to which thistechnology is applicable. For parts based on thermoplastic resins, theprimary processes are referred to as molding processes, i.e. compressionmolding, transfer molding, blow molding, injection molding, rotomolding,and thermoforming. In addition, dies are used. These include stampingdies. Moreover, extrusion dies are used for the fabrication ofthermoplastic resin-based parts, i.e. film, sheet and profiles, e.g.tubes, rods and detailed shapes. This technology applies to all of thesetypes of tools.

[0030] For parts based on thermoset resins, the processes utilize dieforming of the part, such as, sheet pressed in dies to form a partfollowed by cross-linking to achieve strength and related properties. Inaddition, one has molds such as for the fabrication of urethane foamseating and the like. This technology applies to the manufacture of allsuch tooling.

[0031] There are also special part fabrication processes such aspultrusion, filament winding, structural reaction, injection molding,and resin transfer molding. In these processes, one may use a mold ordie. This technology applies to the fabrication of such tooling.

[0032] In all these cases noted above, heat transfer efficiency andthermal control are key to the product quality and manufacturingeconomics of the parts made from the tools. Further, the manufacturingcost and turn around time of the mold, die or forming tool in all thesecases is positively impacted.

[0033] This technology is universal in its applicability to the formingtools and to the parts made from thermoplastic resins, thermoset resins,glass metal, and alloy parts.

[0034] The use of the mold of the present invention allows for theformation of a body portion which can be very easily and rapidly cooled.The reason for such a rapid cooling body portion is that the cavityportion of a mold is applied to the body portion by use of a thermalspraying technique. Preferably, the thermal spraying is applied directlyonto a substrate such as that formed in the body of a metallic portion.

[0035] The invention can also be characterized as the utilization of abody portion formed with controlled porosity. The body portion ispreferably comprised of a foam metallic material such as foamed aluminumor aluminum alloys, or other metallic substances that can be readilyfoamed. Such foamed aluminum alloy is available commercially from AlcanAluminum of Canada, or ERG of California.

[0036] The body portion may also be comprised of other metallicsubstances such as screen or mesh substances. The mesh that can beutilized is one that would have varying sizes of an orifice which wouldpermit, as rapid as possible, flow of coolant of the cavity portion ofthe mold, yet at the same time, having sufficient strength to be used ina molding operation.

[0037] The body portion may also be comprised of other metallicsubstances. One such substance is called “tower packing materials”. Thisline of products is used frequently in the petro-chemical industry tocreate surfaces for cracking condensation and heat transfer. Structuredpackings are available from Nutter Engineering, a unit ofPatterson-Kelly Company, Division of Harsco Corporation of Tulsa, Okla.Such packing materials are called “Montz B1” or “A3” and the like. Thereare other such materials called “Nutter Ring Random Packing” from NutterEngineering. The Nutter Ring is characterized by having an openhalf-ring with perforated center trough, flanged sides, and two taperedspacing hoops of different diameters. Other packing materials that canbe utilized are called “Intalox™ High Performance Structured Packing”from Norton Chemical Process Products of Akron, Ohio. (Intalox™ is atrademark of Norton Chemical Process Products.) The Intalox™ systemlikewise has Snowflakes™ high performance packing which includes doublecorrugated sheet construction of various metals such as copper and thelike. Also, Raschig rings provided by Norton Chemical Process Productscan equally be applicable as well as Hy-pack Metal Packing or Metal PallRings. Other packing materials supplied by Norton are called “Flexipac”which utilizes a number of the aforementioned materials for structuredpacking. Other materials may likewise be utilized, such as “KochFlexigrid” (trademark of Koch) for structured packing materials or“Flexitray” (trademark of Koch) for valve trays or “Flexiring” (dumpedpacking).

[0038] It is to be appreciated, with respect to all of the materialsthat have a configuration that is open and porous, that the materialswould need to be configured or pressed or crushed to a desired size sothat a surface can be adequately prepared for the application of thethermal spraying process.

[0039] Another material that may be utilized for the body of the moldcomponent of the present invention is a sintered metal felt. Thematerial is available to the trade under the trademark, Feltmetal™(trademark of Technetics Corporation of Deland, Fla.). The fiber metalmaterials are sintered and are random metal fiber structures produced inthe form of porous sheets. The materials offer a combination of metallicproperties and make fiber materials suitable for a variety of supportapplications. The alloys that make up the fiber metal can be iron,chromium, aluminum, yttrium, stainless steel, nickel chromium alloys,nickel, copper, and titanium and alloy thereof. The material generallyhas a high porosity of 75%-95% per volume. The fiber metal materials arepermeable with up to 0.05 m²/gm of active surface area. The stainlesssteel materials may, for example, have a density of 10% where the nickelmetal fiber may have a 16% density. A suitable material may be TC3100which is a nickel fiber that has a surface area of 4,000 squarecentimeters of surface per cc of metal volume. The thermal conductivityof the fiber metal materials can be described below in Table I. TABLE IThermal Conductivity of Fiber Metal Materials K Fiber Metal DensityThickness BTU/hr/ K Materials % Inches ft/*F % Solid Nickel 5 0.25 0.130.36 Nickel 17 0.50 0.36 1.0 Stainless 46 1.00 0.28 3.0 Steel

[0040] For comparison, the thermal conductivity of solid nickel is 36.0K BTU/hr/ft/° F. while 302 stainless steel is 9.4. Air is 0.014 for itsthermal conductivity (data derived from Technetics Corporation DataBulletin or TD-882 fiber metal materials). The fiber metal material isdesirable due to its high porosity and therefore ease of cooling andease of configuring for placement of cooling conduits. The fiber metaloffers formability, weldability, resistance to shock and vibration, andload bearing capability in both tension and compression.

[0041] While applicant has described a variety of lightweight molds thatmay be produced using the various metallic substrates, it is to beappreciated that the invention is broadly directed towards tools. Inother words, the invention is directed to dies and other tooling thatare light in weight. Most tooling in the past has been extraordinarilyheavy because the main portion of the tooling is a dense metallic body.Applicant has found by the combination of the thermal spraying that onecan have a body which is extremely light in weight which wouldfacilitate cooling of the tooling. By having such lightweight bodymaterials, the tooling or die or mold can be readily configured to avariety of shapes in a cheaper and easier manufacturing of same.

[0042] In general, the materials for construction for the body portioncan be characterized as a foam, a screen, a felt, tubing, honeycombsintered spheres or packing tower material, and the like in order tohave a controlled porosity.

[0043] The technique of this invention can be used to upgrade cheapmaterials, e.g. thermal spray cast iron substrates.

[0044] The molds or dies are preferably comprised of aluminum and itsalloys, iron and its alloys, e.g. cast iron or nickel and its alloys,e.g., stainless steel.

[0045] In the thermal spraying process, any one of a number ofcommercially available pieces equipment can be utilized. Reference canbe made to the publication “Thermal Spraying”, supra, of the AmericanWelding Society, in particular, chapter 2. The chapter describes typicalwire flame spraying, powder flame spray process, an oxygen fuel gasdetonation gun, an arc spray gun, a plasma torch which is part of aplasma spray system. All of the equipment is commercially available.

[0046] A wide variety of materials can be thermal sprayed onto the bodyforming the cavity of the mold. Suitable materials include metals,metallic oxides, metallic carbides, and metallic nitrides. The metals(oxides, carbides or nitrides) may be Groups 2, through and including 8,of the Periodic Table of Elements. In particular, the metal or metaloxides, metal carbides, or metal nitrides may be aluminum, titanium,silicon, iron, nickel, chrome, zinc, zirconium, calcium, yttrium,magnesium, copper, manganese, molybdenum, tin, antimony, lead, tungsten,boron, and mixtures thereof. In particular, ceramic oxide containingmaterials may be used such as blends of aluminum, titanium, silicon,iron oxides, and the like. Other preferred materials would be iron-basedalloys such as those containing manganese, copper and iron; molybdenum,carbon:and iron; chromium, nickel, molybdenum, silicon, carbon and iron,and the like. Other preferred metallic materials that could be appliedby the thermal spray process would be nickel-based materials, namely,those that contain measurable amounts of nickel such as that from 10% onup to 100% by weight of nickel including various alloys thereofincluding aluminum nickel alloys; chromium, nickel alloys; chromium,aluminum, molybdenum, silicon, iron; boron, nickel alloys; nickel, iron,chrome, manganese and molybdenum alloys such as stainless steel, and thelike. Other materials would be non-ferrous materials such as copperalloys containing aluminum and iron; aluminum alloys containing silicon;high copper alloys containing substantial amounts of copper such as thatcontaining nickel and copper with or without indium; zinc alloys, andcopper zinc alloys; copper tin alloys; copper, silicon carbide alloys;zinc tin alloys; tin, antimony, copper alloys; tin itself; lead itself;lead tin alloys, and the like. Other materials that may likewise beapplied are carbide alloys such as chromium carbide, nickel and chromiumalloys; tungsten carbide and cobalt alloys; tungsten carbide and nickelalloys; titanium carbide and cobalt or nickel alloys; tungsten carbideand nickel, chromium, boron alloys, and the like.

[0047] Other materials that may be applied are refractory metals such astungsten, titanium, molybdenum, or alloys thereof. In addition,self-fluxing alloys may be utilized as a material to be applied in athermal spraying process such as nickel alloys containing chromium,boron, iron, silicon, and carbon, nickel, tungsten carbide, cobalt,chromium, iron, silicon, boron, and carbon alloys; tungsten carbide,cobalt, nickel, chromium, boron, iron, silicon and carbon, and the like.

[0048] Other materials that could be applied are tungsten carbides suchas those that contain alloying amounts of cobalt and iron or tungstencarbide with cobalt by itself or tungsten containing substantial amountsof nickel, carbon, chromium, and the like.

[0049] Additional materials that may be applied are abradable coatingssuch as those contain boron nitride plus nickel alloy materials; nickelplus graphite composites; silicon, aluminum graphite composites;aluminum plus a polyester material; silicon, aluminum, polyimidematerial; aluminum, bronze plus boron carbide cermet material; nickelplus a graphite composite material, and the like.

[0050] A preferred class of materials that would applied would be thenickel aluminum alloys, in particular, nickel aluminide. It is mostpreferred that the material that is to be applied as the cavity to thebody would be one that has a very high thermal conductivity. Listed inTable II below are materials that may be used because of their preferredthermal conductivity where the left hand margin indicates watts perthousand degree Kelvin as the normal conductivity measurement. TABLE IIThermally Conductive Materials Of Interest WATTS/METER K^(.) MATERIAL400 Silver (Pure) Copper (Pure) Cu/B₄C Gold 300 Cu/Ww Al/SiCw Aluminum(Pure) Cu/NI 200 Phosphor Bronze Beryllium (Pure) Titanium (Pure) AINMagnesium Tungsten SiC Al/SiCw Molybdenum CU/Ni/Si NiAl (Composite)Duplex Aluminum, Mold Alloys TiB₂ Cobalt, Nickel, Chromium WC/Co IronCu/Al/Fe Steel Stainless Stellite (cobalt chromium tungsten alloys)

[0051] If the thermal spraying process utilizes wire which is heated andpassed along through a gun apparatus, the wire would be comprised of thedesired metallic component and sprayed onto the substrate.

[0052] It is to be appreciated that the spraying could take place invarious atmospheres such as an atmosphere containing oxygen, nitrogen,and other reactive gases or non-reactive gases. The gases may react withthe metallic material as it is sprayed or after it is in a molten stateon the substrate. The resulting coating may have different portions ofthe gas/metal mixture as a portion of the cavities, by virtue of thespraying process in a desirable atmosphere. Preferably, however, theatmosphere is ambient air atmosphere which is a combination of oxygenand nitrogen.

[0053] The coating thickness that is to be applied can range from 0.1millimeters to 50 millimeters, preferably, 0.5 to 20 millimeters, andeven more preferably, 0.5 to about 5 millimeters.

[0054] It is to be appreciated that one may vary the thermal sprayingmaterials based upon the end use of the mold. It may be desirable tohave a first layer of a thermal spraying process which would be ananchoring layer with the substrate. A more durable or a higher strengthmaterial could then be applied onto the initial layer.Therefore,,multiple layers may be applied to the body of the mold toachieve a cavity having a combination of properties, namely, goodadherence to the substrate, and high durability for the compressioninvolved in the molding operation.

[0055] It is to be appreciated that the coatings as applied may requiresubsequent processing steps such as buffing and polishing, grinding ormachining, and the like, as is well known in the art.

[0056] It is likewise to be appreciated that the post treatment of thethermal sprayed coatings can take a variety of steps such as sealers orother corrosion protection. Preferably, however, a post treatment ofheating or fusion may be utilized as desired. Other post treatmentscould include coating by impingement, electrolytic plating, electrolessplating, nitriding, anodizing, and the like.

[0057]FIG. 1 shows the mold 10 of the present invention. A metallic bodyportion 12 has a cavity portion 14. Shown is a cavity for a blow moldedbottle with a top portion 16. FIG. 1 is a perspective view of the mold,while FIG. 2 is a cross-section of the mold taken along lines 2-2 ofFIG. 1. The thermal spray is applied in a process that would permit ahigh volume such as a movable conveyor 18 which passes the mold 10within an appropriate distance from the gun 18. The gun has an inlet 20for powder particles to be inserted therein from a hopper (not shown). Afuel gas inlet 22 can be ignited, thereby warming the powder to themolten state. There is optionally also an oxygen inlet 24 to assist incombustion. Particles thereby are sprayed through outlet 26, whichparticles 28 are now in the molten form schematically shown as a sprayin FIG. 3. The mold 10, after the application of thermal spray, then hasthe cavity portion coated with the thermal spray coating 30. The outletportion of the gun 26 may nave placed thereon a coating to facilitatethe movement of the particles through the outlet. This coating isgenerally a disulfide or a sulfide material of metallic character suchas titanium, molybdenum, tantalum, and the like. The coating isgenerally applied by chemical vapor deposition utilizing techniquesknown in the art.

[0058] After an appropriate pair of molds are formed, they are heldtogether in a molding process such as a blow molding process, as shownin FIG. 4. This demonstrates that the process permits the formation of ablow molded product such as a milk container 32, schematically shown inFIGS. 4 and 5, where the molding occurs in FIG. 4, while FIG. 5 showsthe release of the blow molded product 32.

[0059] The mold of the present invention can be used for a variety ofend uses. A preferred use is the application of the mold in theformation of plastic products. The plastic that may be utilized is onethat can be blow molded, injection molded, and other molding techniques.The molding may also include a RIM process (reaction injection molding).The plastic materials may be thermoplastic materials such as those thatsoften upon the application of temperature and upon cooling conform to anew shape. A subsequent application of heat would allow the material totake on a new shape as desired. Thermoset materials are those that setwithin application of temperature and/or pressure and/or catalysts to afixed and firm position. A subsequent application of a heat does notpermit deformation, but rather destruction; of the bonds involved in theformation of the thermoset final product in the first place. Examples ofthermoplastic materials are polystyrene, acrylonitrile, styreneacrylonitrile, polyvinyl chloride (PVC), polyethylene terephthlate(PET), polysulfone, polyethylene, polypropylene, high density and lowdensity polyethylene materials, nylon materials, (polyamides), oxygenbarrier materials such as PET, PPOH, PVDC (polyvinyl dichloride),polytetrafluoroethylene (PTHFE), polyvinylidene chloride, polypropylene,polybutylene, polyisobutylene, and the like. With respect to thermosetmaterials, such materials may be epoxy materials, polyurethanematerials, polyester materials, polyacetates, polycarbonates,poly(methyl)methacrylates, and the like. Also to be contemplated asplastic materials would be elastomeric such as rubber materials orsynthetic rubber materials, styrene butadiene, isopropylene, and thelike.

[0060] In general, if one utilizes the lightweight molds of the presentinvention for the thermal application o thermoset materials, the desiredcharacteristics of the tooling would be to have good heat control, goodheat transfer efficiency, wear resistance and chemical resistance. Thetools that would be utilized are thermal forming tools or dies as wellas injection molds. The materials that would preferably be utilized areurethanes, such as flexible foams, rigid foams and solids. Othermaterials would be epoxies; phenolics, such as novolacs; amines, such aspolyamines; silicones, such as methochlorosilane; composites, such asengineering materials; thermoset polyesters and wood-containingmaterials; allyls, such as polyester resins derived from esters of allylalcohol and dibasic acids. Common monomers are allyl diglycol carbonate,also known as diethylene glycol bis (allyl carbonate), diallylchlorendate, diallyl phthalate, diallyl isophthalate and diallylmaleate.

[0061] The present invention is likewise applicable towards the shaping,forming and molding of thermoplastics. In that situation, the toolingshould have the desired characteristics of having good thermal control,high-heat transfer efficiency, wear resistance as well as chemicalresistance. The tooling that would be utilized would generally be blowmolds, injection molds, as well as thermoform dies. The most preferredmaterials that would be formed are thermoplastic materials such aspolystyrenics; ABS (acrylonitrile/butadiene/styrene); SAN(styrene/acrylonitrile polymer); polyethylene; polypropylene;polycarbonates; polysulfones; polyethylene terephthalates; polyamidessuch as nylon and the like; glass materials and metals such as aluminum,aluminum alloys, zinc and zinc alloys, copper, copper alloys, tin andtin alloys.

[0062] Another distinct advantage of the present invention is that thebody in which the cavity is sprayed thermally is formed of material thatis readily machined. Due to the ease of the machining of aluminum orwire mesh (or metal felt (fiber)) materials, a CAD/CAM device can beutilized to simplify the manufacture of a mold. After one selects theend use of the mold, namely the product to be molded, one can machinethe mold reasonably inexpensively and quickly with a CAD/CAM device. Dueto the wide-open nature of the body of the mold, it is relatively easyto machine to a desired configuration. In addition, due to the wide-opennature of the body of the mold, it is highly porous. The porosity wouldfacilitate cooling of the mold, thereby increasing cycle time formolding operations.

[0063] More broadly, the molds, dies and forming tools can be designedto optimize the heat transfer efficiency for whatever part manufacturingtask is to be done. The rate limiting step to the manufacturing cyclenormally consists of the rate of heat flow through the plastics plus therate of heat flow from the mold. With the technology described herein,one can significantly decrease the heat flow contribution from the mold.Hence, the manufacturing cycle time for plastic part production can bedecreased significantly.

[0064] A wide variety of shapes can be molded. The appropriateconfiguration for the mold can be designed utilizing a CAD CAMtechnique. Three dimensional datasets for a particular configuration canbe obtained from Viewpoint Corporation's (of Oren, Utah) datasetcatalog. The dataset could be of a bottle, whether it be plastic orglass, or other industrial configuration such as beepers, telephonehandsets, computer keyboards, computer covers, gavels, guitars, and thelike. With utilization of such 3-D datasets, one can then configure themold that would be used to form the final end product utilizing thetechniques as described herein for the convenient shaping of the molditself.

[0065] Some particular uses of the molds for fabrication are describedbelow.

[0066] One could use the molds of the present invention for thefabrication of urethane foam parts for automotive seating. The desiredmold characteristics would be that they would have an isothermal moldingsurface, moderate heat transfer efficiency, moderate compressionstrength, good release surface (renewable) long-wearing closuresurfaces, and be lightweight. The desired mold body would be comprisedof aluminum. The materials of construction for the mold body wouldpreferably be a screen or a foam or jack straws or a honeycombstructure, or the power-packing media as described above. The materialsof construction for the mold cavity would preferably be aluminum, oraluminum graphite spheres, or ultra high molecular weight polyethylene.For the latter technique, the high melting temperature polyethylenewould be stable at the foam formation temperature of the urethane, whichis generally 150-200° F. The polyethylene is stable at that temperatureand the foamed urethane may be separated therefrom.

[0067] It is to be appreciated that the application of the ultra highmolecular weight polyethylene will use commercially available equipment.It is usually different than that used for the application of metals.Such equipment may be similar to that used in powder coating processes.The powder is generally applied by an air atomization process (chargedor otherwise) directly onto a heated substrate which is then subjectedto a heat curing process.

[0068] It should also be appreciated that a variety of high temperaturethermoset or thermoplastic powder materials may be coated. They may bepolyethylene, polypropylene, epoxies, polyamides as nylons,(meth)acrylics, polyphenylene sulfide, polysulfone, polybenzimidazole,and the like.

[0069] When a plastic powder material is used, the cavity is preferablypreviously formed by the thermal sprayed metallic particles as describedherein. This provides a smoother surface for the application of theplastic powder.

[0070] The molds of the present invention could also be used for thefabrication of plastic containers via blow molding. In that situation,the desired mold characteristics would be an isothermal molding surface,a high heat transfer efficiency, moderate compression strength for thecavity, high quality finish, lightweight, non-corroding surface finish,and a high compression strength for the mold closure surfaces. The bodymold would be comprised of aluminum. The materials of construction forthe lightweight portion of the mold body would be preferably a screen,or foam, or felt, or packing-tower media. The materials of constructionfor the mold cavity would preferably be aluminum with nickelelectroplated on top or aluminum with trinickel aluminide on top oraluminum with titanium nitride on top.

[0071] The tooling for fabrication of aluminum diecasting would be of anature that the mold or the die would have a high resistance to thermalcycle fatigue and thermal shock during mold filling and emptying. Inother words, there would need to be high, hot strength and toughness aswell as having high thermal conductivity, that is, greater than about100 watts/meter—Kelvin, as well as have low coefficient of thermalexpansion. The tooling likewise would need to have high resistance ofthe materials of construction to erosion and wetting by the moltenaluminum. In other words, low solubility of materials of construction inmolten aluminum, high thermodynamic stability of the materials ofconstruction in relationship to molten aluminum, and lastly, have highmelting point for the materials of construction. The materials ofconstruction for the tool body preferably would becopper/dichromium-niobide, nickel or stainless steel, or nickelaluminide. The form of the materials of construction for the body of thetooling would be preferably foam, or screen, or felt, or tubing, orhoneycomb, or perforated sheet/plate, or sintered walls. The materialsof construction for the cavity membrane would preferably be nickelaluminide/nickel aluminide molybdenum/molybdenum; trinickelaluminide/trinickel aluminide-molybdenum/molybdenum; nickelaluminide/nickel aluminide-molybdenum/molybdenum; nickel/nickelmolybdenum/molybdenum; nickel/nickel-boron/nickel boron/trinickelaluminide; molybdenum; molybdenum/molybdenum-boron/molybdenum boron.With respect to the details of construction for the mold, one shouldcombine the solid petitions and low density volumes as required. Aninexpensive filler may be used in the bottom of the mold. One can alsouse an open matrix structure so as to enlarge the thermal sprayedmembrane. One can also use a structure which can be readily recycled andrepaired.

[0072] As to the tooling for the fabrication of molten glass, theproperties of the tooling should be such that they are resistant tothermal cycle fatigue and thermal shock. In other words, the toolingshould have superior high strength and toughness as well as have lowthermal coefficient of thermal expansion and have an adequately highthermal conductivity (greater than 100 watts/meter—Kelvin). In addition,the tooling should have a high resistance to the corrosive action ofmolted glass. The materials should have a high melting point, yet havelow solubility of the materials of construction in molten glass. Thetooling should have surface modifications which permit a protectivecoating to the working surface of the tools. The tooling should havehigh resistance to the oxidizing strength of molten glass yet have highthermal conductivity stability of the materials of construction tomolten glass. The tooling should have surface modifications which permitprotective coating to the working surface of the tools yet have a highwear-resistance to the wear of the working surface of the tool createdby the molten glass. The tooling should have a high hot hardness. Thetooling should have a high modulus at elevated temperatures, high glosssurface for aesthetics, and have a fine grain size via thermoplasmaspray coating of fine powders used for the materials of construction ofthe cavity membrane or coating.

[0073] The materials of construction for the tool body are preferablynickel, chromium/dichromium niobide, stainless steel, iron steel,graphite, nickel carbide, or nickel aluminide.

[0074] The form of materials of construction for the body itselfpreferably would be a foam or a screen or sintered walls, or tubes orhoneycombs, or felt.

[0075] The materials of construction for the cavity membrane may be asfollows (multiple layers as indicated):

[0076] Ni—Al/Ni—Al—Mo/Mo

[0077] Ni3Al/Ni3Al—Mo/Mo

[0078] NiAl/NiAl—Mo/Mo

[0079] Ni/Ni—Mo/Mo

[0080] Ni/Ni—B/NiB

[0081] Ni3Al

[0082] Mo

[0083] Mo/Mo—B/MoB

[0084] The tooling for the fabrication of the molding compound-basedparts are as follows. The tool characteristics should have an isothermalmolding surface; 300° F. operating temperature; mar and wear-resistantsurface; class A, super finish surface; 3-500 psi (minimum) compressionstrength; be lightweight and reasonably good heat transfer efficiency.The materials have of construction would be aluminum and stainless steelpreferably. The types of materials of construction for the tool bodywould be screen or packing-tower material, or jack straws, or honeycomb,or foam, or felt. The materials of construction for the tool formingsurfaces would preferably be aluminum/nickel aluminide oraluminum/electrolytic application of nickel, or stainless steel.

[0085] While the forms of the invention herein disclosed constitutepresently preferred embodiments, many others are possible. It is notintended herein to mention all of the possible equivalent forms orramifications of the invention. It is understood that the terms usedherein are merely descriptive rather than limiting and that variouschanges may be made without departing from the spirit or scope of theinvention.

What is claimed is:
 1. A mold or die comprising a porous heat exchangingbody support member having a defined porosity; and within the supportmember a molding cavity portion formed by applying a metallic surface toa desired configuration in the support member.
 2. The mold or die ofclaim 1 wherein the sprayed particles are metallic.
 3. The mold or dieof claim 1 wherein the sprayed particles are plastic.
 4. The mold or dieof claim 1 wherein the body is comprised of a foamed metal.
 5. The moldor die of claims 4 wherein the foamed metal is comprised of aluminum. 6.The mold or die of claim 1 wherein the body is comprised of wire screenmembers having apertures for flow of coolant therethrough.
 7. The moldor die of claim 1 wherein the mold cavity has the strength to formmolded plastic pieces.
 8. The mold or die of claim 1 wherein the moldcavity has the strength to form molded metallic pieces.
 9. The mold ordie of claim 1 wherein the body support member is porous metal.
 10. Themold or die of claim 1 wherein the body support member is comprised offelt metal.
 11. The mold or die of claim 1 wherein the body supportmember is comprised of fibrous metal.
 12. The mold or die of claim 1wherein the body support member is comprised of metallic structuredpacking.
 13. The mold or die of claim 1 wherein the body support memberis comprised of metallic tower-packing.
 14. The mold or die of claim 1wherein the body support member is comprised of metallic Raschig rings.15. The mold or die of claim 1 wherein the body support member iscomprised of corrugated wire gauze.
 16. The mold or die of claim 1 beingcharacterized as a mold for the fabrication of urethane foam parts. 17.The mold or die of claim 1 being characterized as a mold for thefabrication of plastic containers.
 18. The mold or die of claim 1 beingcharacterized as tooling for the fabrication of aluminum.
 19. The moldor die of claim 1 being characterized as tooling for the fabrication ofmolten glass.
 20. The mold or die of claim 1 being characterized astooling for the fabrication of low pressure sheet molding compound-basedparts.
 21. A tool for shaping a material comprising: (a) a porous heatexchanging body support member having a defined porosity; and (b) withinthe support member a molding surface portion formed by a metallicsurface to a desired configuration in the support member.
 22. The toolof claim 21 comprised of a die.
 23. The tool of claim 21 wherein thesprayed particles are metallic.
 24. The tool of claim 21 wherein thesprayed particles are plastic.
 25. A method of making a mold or diecomprising the steps of: (a) providing a porous heat exchanging bodysupport member having a defined porosity; (b) configuring a surface ofthe support member to a desired cavity; and (c) applying to theconfigured cavity in the support member a metallic surface therebyproducing a mold or die.
 26. The method of claim 25 wherein the sprayedparticles are metallic.
 27. The method of claim 25 wherein the sprayedparticles are plastic.
 28. The method of claim 25 wherein the body iscomprised of a foamed metal.
 29. The method of claim 28 wherein thefoamed metal is comprised of aluminum.
 30. The method of claim 25wherein the body is comprised of wire screen members having aperturesfor flow of coolant therethrough.
 31. The method of claim 25 wherein themold cavity has the strength to form molded plastic pieces.
 32. Themethod of claim 25 wherein the mold cavity has the strength to formmolded metallic pieces.
 33. The method of claim 25 wherein the moldcavity has the strength to form molded plastic pieces.
 34. The method ofclaim 25 wherein the mold cavity has the strength to form moldedmetallic pieces.
 35. The method of claim 25 wherein the body supportmember is porous metal.
 36. The method of claim 25 wherein the bodysupport member is comprised of felt metal.
 37. The method of claim 25wherein the body support member is comprised of fibrous metal.
 38. Themethod of claim 25 wherein the body support member is comprised ofmetallic structured packing.
 39. The method of claim 25 wherein the bodysupport member is comprised of metallic tower-packing.
 40. The method ofclaim 25 wherein the body support member is comprised of metallicRaschig rings.
 41. The method of claim 25 wherein the body supportmember is comprised of corrugated wire gauze.
 42. A method of molding aproduct comprising the steps of: a) providing the mold or die of claim1; b) inserting a material to be molded into the cavity of the mold; c)molding the product; and d) recovering the product.
 43. The method ofclaim 42 wherein the sprayed particles are metallic.
 44. The method ofclaim 42 wherein the sprayed particles are plastic.
 45. The method ofclaim 42 wherein the body is comprised of a foamed metal.
 46. The methodof claim 42 wherein the foamed metal is comprised of aluminum.
 47. Themethod of claim 42 wherein the body is comprised of wire screen membershaving apertures for flow of coolant therethrough.
 48. The method ofclaim 42 wherein the molded product is metallic.
 49. The method of claim42 wherein the molded product is a thermoplastic product.
 50. The methodof claim 42 wherein the molded product is a thermoset product.
 51. Themethod of claim 42 wherein the molded product is an elastomeric product.52. The method of claim 42 wherein the body support member is porousmetal.
 53. The method of claim 42 wherein the body support member iscomprised of felt metal.
 54. The method of claim 42 wherein the bodysupport member is comprised of fibrous metal.
 55. The method of claim 42wherein the body support member is comprised of metallic structuredpacking.
 56. The method of claim 42 wherein the body support member iscomprised of metal tower-packing.
 57. The method of claim 42 wherein thebody support member is comprised of metallic Raschig ring.
 58. Themethod of claim 42 wherein the body support member is comprised ofcorrugated wire gauze.
 59. A method for shaping a product comprising thesteps of: a) providing the tool of claim 21; b) shaping a material byinserting the molding surface of the tool into direct contact with thematerial and shaping it to a desired configuration; and c) recoveringthe product.
 60. The method of claim 59 comprised of a die.
 61. Themethod of claim 59 being characterized as a mold for the fabrication ofurethane foam parts.
 62. The method of claim 59 wherein the product iscomprised of a plastic container.
 63. The method of claim 59 wherein theproduct is comprised of aluminum.
 64. The method of claim 59 wherein theproduct is comprised of molten glass.
 65. The method of claim 59 whereinthe product is comprised of a low pressure sheet molding compound-basedpart.